Pneumovax vs vaccinum

Pneumovax and vaccinum both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pneumovax	Yes	No	No	No
vaccinum	Yes	No	No	No

As nouns, vaccinum is a hypernym of Pneumovax; that is, vaccinum is a word with a broader meaning than Pneumovax:

Pneumovax: vaccine (trade name Pneumovax) effective against the 23 most common strains of pneumococcus
vaccinum: immunogen consisting of a suspension of weakened or dead pathogenic cells injected in order to stimulate the production of antibodies

Other hypernyms of Pneumovax include vaccine.

Pneumovax (noun)	vaccinum (noun)
vaccine (trade name Pneumovax) effective against the 23 most common strains of pneumococcus	immunogen consisting of a suspension of weakened or dead pathogenic cells injected in order to stimulate the production of antibodies